Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/005—Dendritic macromolecules
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

Definitions

• the invention relates to a process for the production of a modified polyester with improved rheological and mechanical properties according to claim 1, to a product produced by the process according to the invention with improved mechanical properties according to claim 18 and to an additive package which can be used for the production of such a modified polyester Claim 20.
• polyester It is known to process polyester together with reactive additives to improve the rheological and mechanical properties. If this processing takes place in the melt, for example in an extruder, the polyester is also subjected to various degradation reactions which limit the achievement of a high molecular weight or even counteract it at the same time as the build-up reaction with the reactive additive.
• an inhomogeneous mixture of highly crosslinked particles or gels can be formed in an otherwise low molecular weight matrix.
• the object of the invention is therefore to provide a method in which a large number of polyester chains are linked to form macromolecules with a high degree of branching and a very high molecular weight, but without producing a significant amount of crosslinking.
• HBP hyperbranched polymer
• both the degree of branching and the degree of crosslinking of the macromolecules can be influenced in a targeted manner.
• more branching of the individual separate molecules and at the same time less crosslinking of the molecules can achieve high melt strength with low brittleness (high breaking strength) of the solidified melt (end product).
• a polyester in particular a thermoplastic polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or polycarbonate is used. Both virgin material and recycled material, in particular in the form of recycled PET bottle chips, can be used.
• the polyester material can be present as a homopolymer or as a copolymer, the molecular weight of the polyester, measured as intrinsic viscosity IV, being between 0.2 and 1.0, typically between 0.6 and 0.85 dl / g.
• Recycled material comprises material that is produced as consumer recyclate as well as industrial recyclate from products such as bottles, foils or fibers and is either processed directly or sorted, washed and shredded beforehand.
• hyperbranched polymer HBP
• hyperbranched dendritic macromolecules hyperbranched dendritic macromolecules
• three-dimensional, highly branched molecules with a structural branching structure are generally referred to. These include the highly symmetrical dendrimers, as well as similar structures with a higher degree of asymmetry.
• Hyperbranched dendritic macromolecules consist of a core with one or more reactive sites or functional groups and a number of branching layers consisting of one or more branched chain extenders with at least three reactive sites or functional groups, and optionally one or more spacer layers and / or a layer terminating chain Molecules or functional groups, wherein at least one reactive site or functional group can react with a reactive site of the polymer into which the HBP is to be incorporated and can lead to a connection.
• Preferred functional groups for the reaction with polyester are, for example, hydroxyl, epoxy, anhydride or carboxyl groups.
• the HBP can be added alone or as part of an additive package. Additives from the group of impact modifiers, nucleating agents, catalysts, dyes and pigments, stabilizers, compatibilizers, molecular weight-increasing or elasticity-increasing additives, reinforcing fibers or fillers are also used to produce the additive package.
• a carrier material can be used, in which all additives can be incorporated.
• the additive package can be present both as a homogeneous powder or granulate and as a simple additive mixture.
• the mixing and melting of the polyester with the HBP can be carried out in an extruder, kneader or other suitable apparatus, such as, for example, a melt polymerization reactor as used in the production of polyester.
• a melt polymerization reactor as used in the production of polyester.
• Both single-screw and twin-screw extruders as well as multi-screw extruders such as a ring extruder or planetary extruder are suitable as extruders.
• the polyester and the HBP can be introduced into the mixing apparatus both simultaneously and in succession.
• the HBP can be added as a solid to the polyester in the solid as well as in the molten state. It is also possible to melt the polyester and the HBP in separate machines and only then mix them.
• the HBP can react with the polyester during melting and mixing.
• the process should be carried out in such a way, in particular by controlling the residence time and the temperature, that not all free reactive end groups react with the polyester.
• To process the polyester it is advisable to remove water from the polyester and possibly also the HBP. This takes place according to known drying processes either in a separate dryer or in an extruder, as long as the materials are still in the solid state or also by degassing the melt.
• Further process steps can follow the melting process, such as melt degassing, melt filtration, mixing in and homogenizing further additives or building up pressure to shape and convey the material.
• the molten material is returned to the solid form by cooling in contact with a suitable cooling medium, such as air, water or a cooled surface.
• a suitable cooling medium such as air, water or a cooled surface.
• the material is preferably first pressed through a shaping nozzle or into a mold.
• a common method is granulation, for example by strand granulation or head granulation. However, films or other shaped pieces can also be used, if appropriate after comminution.
• Solid-phase post-condensation and crystallization During the solid-phase post-condensation step, some or all of the still free reactive end groups of the HBP react with the polyester. At the same time, the molecules of the polyester react with each other. Both lead to an increase in the molecular weight, depending on the amount of HBP and completeness of the reaction, a branched or crosslinked modified polyester is formed. In many cases, crosslinking is not desirable (brittleness), and the HBP concentration and process conditions are chosen so that a branched, modified polyester is formed.
• the solid phase post-condensation can be carried out either continuously or as a batch process under vacuum or in a gas stream, such as, for example, air, nitrogen, water vapor or carbon dioxide.
• a step of crystallization Before the step of solid phase post-condensation, a step of crystallization usually has to be carried out. This crystallization step can take place as part of the cooling or granulation process or also within the post-condensation reactor. However, the crystallization step can also be carried out in a separate process step. consequences. Reactors with mechanical stirrers in which the product is heated or apparatuses in which the product is heated and agitated by a gas stream, such as, for example, in a fluidized bed, fluidized bed or fluidized bed apparatus, are typically used. Crystallization can take place in one or more steps.
• the solid phase post-condensation can be followed by a further step for cooling or further processing. Cooling can take place as part of the post-condensation process or in a separate process step.
• a polyester granulate (Eastman, 9921 W) was ground and dried in vacuo at 105 ° C. for 12 hours.
• the material was extruded in a rotating twin-screw extruder (Prism TSE 16) at 220 ° C in the feed area, 265 ° C melting and conveying area and 240 ° C at the die and then pelletized.
• the solution viscosity (IV) in phenol / dichlorobenzene and the elongation viscosity at 270 ° C. using a capillary rheometer with a pull-off device were measured and the tensile stress at the respective degrees of stretching was determined therefrom.
• the tensile stress is calculated according to: F * (Vf -Vo) / Ad / Vo
• Ad nozzle area
• Example 3 2 kg of the extruded polyester granulate from Example 1 was then crystallized for 20 minutes at 175 ° C. in air in a fluid bed reactor. 0.5kg of this was post-condensed in a nitrogen stream at 210 ° C. for 7 hours and then rapidly cooled. Again succeeded . a determination of the tensile stress at given degrees of stretch and the IV.
• Example 3 2 kg of the extruded polyester granulate from Example 1 was then crystallized for 20 minutes at 175 ° C. in air in a fluid bed reactor. 0.5kg of this was post-condensed in a nitrogen stream at 210 ° C. for 7 hours and then rapidly cooled. Again succeeded . a determination of the tensile stress at given degrees of stretch and the IV.
• Example 3 2 kg of the extruded polyester granulate from Example 1 was then crystallized for 20 minutes at 175 ° C. in air in a fluid bed reactor. 0.5kg of this was post-condensed in a nitrogen stream at
• HBP Perstorp, Bolteron H20, a two-layer dendritic polymer with theoretically 16 primary hydroxyl groups and a molecular weight of 1747 g / mol
• Extruded product from Example 3 was processed and measured analogously to the conditions from Example 2, but the post-condensation was carried out at 210 ° C. for 5 hours.
• Example 3 was repeated with 0.1% of the HBP.
• Extruded product from Example 5 was processed and measured analogously to the conditions from Example 2, but the post-condensation was carried out at 210 ° C. for 4 hours.
• Example 3 was repeated, however, with 0.04% of an HBP (Perstorp, Bolteron H40, a four-layer dendritic polymer with theoretically 64 primary hydroxyl groups and a molecular weight of 73.16 g / mol).
• HBP Perstorp, Bolteron H40, a four-layer dendritic polymer with theoretically 64 primary hydroxyl groups and a molecular weight of 73.16 g / mol
• Extruded product from Example 7 was processed and measured analogously to the conditions from Example 2, but the post-condensation was carried out at 210 ° C. for 6 hours.
• Example 7 was repeated, however, with 0.1% of the HBP.
• Example 10 is repeated, however, with 0.1% of the HBP.
• Extruded product from Example 9 was processed and measured analogously to the conditions from Example 2, but the post-condensation was carried out at 210 ° C. for 5 hours.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyesters Or Polycarbonates (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

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Citations (7)

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• 2001
  • 2001-07-03 DE DE10132928A patent/DE10132928A1/de not_active Withdrawn
• 2002
  • 2002-03-26 MX MXPA03011762A patent/MXPA03011762A/es unknown
  • 2002-03-26 PL PL02367629A patent/PL367629A1/xx not_active Application Discontinuation
  • 2002-03-26 ES ES02704541T patent/ES2253513T3/es not_active Expired - Lifetime
  • 2002-03-26 WO PCT/CH2002/000177 patent/WO2003004546A1/de not_active Application Discontinuation
  • 2002-03-26 CN CNA028134621A patent/CN1522269A/zh active Pending
  • 2002-03-26 DE DE50205208T patent/DE50205208D1/de not_active Expired - Lifetime
  • 2002-03-26 AT AT02704541T patent/ATE312129T1/de not_active IP Right Cessation
  • 2002-03-26 EP EP02704541A patent/EP1401911B1/de not_active Expired - Lifetime
• 2003
  • 2003-12-31 US US10/748,203 patent/US20040192857A1/en not_active Abandoned

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